A prospective examination of Axis I psychiatric disorders in the first 5 years following moderate to severe traumatic brain injury

Abstract

Background: Psychiatric disorders commonly emerge during the first year following traumatic brain injury (TBI). However, it is not clear whether these disorders soon remit or persist for long periods post-injury. This study aimed to examine, prospectively: (1) the frequency, (2) patterns of co-morbidity, (3) trajectory, and (4) risk factors for psychiatric disorders during the first 5 years following TBI.

Method: Participants were 161 individuals (78.3% male) with moderate (31.2%) or severe (68.8%) TBI. Psychiatric disorders were diagnosed using the Structured Clinical Interview for DSM-IV, administered soon after injury and 3, 6 and 12 months, and 2, 3, 4 and 5 years post-injury. Disorder frequencies and generalized estimating equations were used to identify temporal relationships and risk factors.

Results: In the first 5 years post-injury, 75.2% received a psychiatric diagnosis, commonly emerging within the first year (77.7%). Anxiety, mood and substance-use disorders were the most common diagnostic classes, often presenting co-morbidly. Many (56.5%) experienced a novel diagnostic class not present prior to injury. Disorder frequency ranged between 61.8 and 35.6% over time, decreasing by 27% [odds ratio (OR) 0.73, 95% confidence interval (CI) 0.65-0.83] with each year post-injury. Anxiety disorders declined significantly over time (OR 0.73, 95% CI 0.63-0.84), whilst mood and substance-use disorder rates remained stable. The strongest predictors of post-injury disorder were pre-injury disorder (OR 2.44, 95% CI 1.41-4.25) and accident-related limb injury (OR 1.78, 95% CI 1.03-3.07).

Conclusions: Findings suggest the first year post-injury is a critical period for the emergence of psychiatric disorders. Disorder frequency declines thereafter, with anxiety disorders showing greater resolution than mood and substance-use disorders.

Keywords: Anxiety; depression; longitudinal studies; psychiatric disorders; traumatic brain injury.